For some hypertension (high blood pressure) risk groups, it may be necessary to monitor blood pressure status frequently, in various locations, and at any number of different times of day. One significant hypertension risk group is elderly individuals (≥65 years old). It has been estimated that 65% of elderly people in the United States have hypertension. Another hypertension risk group is overworked individuals. A study has shown that people who work 51 hours report hypertension 29% more than individuals who work between 11 and 39 hours per week. Yang, et al, Work Hours and Hypertension, Hypertension 48:744-750 (2006). In addition, excessive overwork may increase the risk of sudden death (sometimes known as karōshi death) risk. Obese individuals also have a significantly increased risk of hypertension. In particular, many clinical studies have shown that overweight individuals may have elevated low-density lipoprotein cholesterol and an increased risk of cardiovascular disease.
Regular measurement and evaluation of blood pressure and other physiological parameters is often advised for individuals in these high-risk groups. Current blood pressure measuring devices, however, are not well suited to the task of regular physiological assessment. The standard method for measuring blood pressure is the oscillometric technique. This measurement technique requires the use of a blood pressure cuff on an arm or in another position (such as a wrist or a finger) and may underestimate or overestimate blood pressure, if the cuff is too large or too small. Moreover, incorrect posture may produce inaccurate readings. The excessive pressure produced by a blood pressure cuff during the reading may make the user uncomfortable. In addition, most blood pressure measurement devices are large and need a line to connect the cuff and a measuring apparatus, which makes the device difficult to carry and inconvenient to operate. As a result, cuff-based blood pressure measuring devices are inconvenient and difficult to use for daily measurements.
For example, cuff-type devices may be too large to be carried easily and used regularly, which may limit high-risk individuals to taking physiological measurements only in a hospital or at home. Because these individuals may struggle to monitor and record physiological measurements frequently and in multiple different locations and at different times, they may be unable to take proper precautions and improve their health. Although cuffless, portable physiological measurement devices have been developed, they are often unable to provide accurate blood pressure readings. In addition, while most people know that elevated blood pressure may indicate cardiovascular disease, they do not understand what the measurements mean or how to use the measurements to improve their health.
Therefore, it would be advantageous to have improved devices and methods for measuring blood pressure and, possibly, one or more additional physiological parameters. It would also be advantageous to have devices and methods for providing blood pressure measurement data to a patient in a form that the patient could easily understand and use to improve his or her health. Ideally, such devices would be very portable and easy to use in almost any location, so that a patient could easily measure his or her own blood pressure (and possibly other parameters), without the assistance of a physician or nurse and without needing to go to a hospital or clinic. At least some of these objectives will be addressed by the embodiments described below.